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If I have the following code :
threads = [] (1..5).each do |i| threads << Thread.new { `process x#{i}.bin` } end threads.each do |t| t.join # i'd like to get the output of the process command now. end What do I have to do to get the output of the process command? How could I create a custom thread so that I can accomplish this?
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How to Return Values From a Thread. A thread cannot return values directly. The start() method on a thread calls the run() method of the thread that executes our code in a new thread of execution. The run() method in turn may call a target function, if configured.
The function foo below returns a string 'foo' .
The Ruby Interpreter is single threaded, which is to say that several of its methods are not thread safe. In the Rails world, this single-thread has mostly been pushed to the server.
Threads do not really have return values. However, if you create a delegate, you can invoke it asynchronously via the BeginInvoke method. This will execute the method on a thread pool thread. You can get any return value from such as call via EndInvoke .
The script
threads = [] (1..5).each do |i| threads << Thread.new { Thread.current[:output] = `echo Hi from thread ##{i}` } end threads.each do |t| t.join puts t[:output] end illustrates how to accomplish what you need. It has the benefit of keeping the output with the thread that generated it, so you can join and get the output of each thread at any time. When run, the script prints
Hi from thread #1 Hi from thread #2 Hi from thread #3 Hi from thread #4 Hi from thread #5
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I found it simpler to use collect to collect the Threads into a list, and use thread.value to join and return the value from the thread - this trims it down to:
#!/usr/bin/env ruby threads = (1..5).collect do |i| Thread.new { `echo Hi from thread ##{i}` } end threads.each do |t| puts t.value end When run, this produces:
Hi from thread #1 Hi from thread #2 Hi from thread #3 Hi from thread #4 Hi from thread #5 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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